Diagnosis of urological disorders is often facilitated by a patient's urine flow rate data. Urological disorders such as an obstruction in the lower urological tract or neurotic bladder can be detected by studying the patient's urine flow rate as it varies from the beginning of voiding to the end and the total volume of urine voided. This data can be compared to the mean data for an individual of the same sex and age to help determine the degree of urethral stricture.
Urine flow data is also useful in diagnosing prostrate enlargement. Prostrate enlargement usually occurs gradually with no noticeable impairment to the patient. Merely observing the patient void will usually not enable the urologist or physician to accurately assess the degree of prostate enlargement. However, by observing histograms of the urine flow, the urologist or physician can usually detect the degree of prostrate enlargement and the necessary procedures to be undertaken to correct the disorder. In addition, post-operative urine flow data provides an excellent way of assessing the benefit achieved by surgery.
Several different types of urine flow meters for providing urine flow data are presently commercially available. Examples of a mechanical urine flow meter for enabling manual measurement of urine flow are found in U.S. Pat. Nos. 4,099,412, 4,200,112, 4,241,017, 4,000,649, 4,085,616, 4,301,813 and reissue patent 30,607. These mechanical urine flow measuring devices usually comprise a container having a graduated scale for indicating the volume of urine within the container. Urine flow is detected by manually observing the change in volume as the patient voids into the container. These devices therefore require that either a physician, a nurse or a technician observe the patient void into the container. While a privacy screen is usually provided between the patient and the observer, the patient may still exhibit distress or embarassment knowing that his or her voided stream is being observed.
To overcome this disadvantage, electrical urine flow meters for providing urine flow data have been developed. For example, U.S. Pat. No. 4,187,722 discloses a urine velocity measuring device including a urine flow receptacle having a paddle wheel journaled therein. The paddle wheel is mechanically linked to a generator which produces an output voltage which is displayed on a volt meter. The velocity of the urine stream impinging on the paddle wheel determines the paddle wheel velocity and therefore the output voltage of the generator.
U.S. Pat. No. 4,051,431 discloses another device for measuring a urine flow electrically. The urine flow meter disclosed in this patent includes a urine receiving receptacle which has a pair of parallel spaced-apart rods or strips disposed therein. The rods or strips are electrically connected to a capacitance sensing circuit. As the volume of urine within the receptacle increases, the capacitance between the rods also increases so that by measuring the rate of change of the capacitance, an indication of the urine flow may be obtained.
Both of the above described electrical urine flow meters require a high degree of maintenance. Since urine contacts components of each of the meters, those components must be cleaned following each use. Therefore, a need exists for a low maintenance electrical urine flow meter.